As a luminescent material (green emitting luminescent material) which exhibits green emission by excitation with blue light, an Eu-activated alkaline earth orthosilicate luminescent material has recently been suggested. A white light-emitting device is configured using the green emitting luminescent material in combination with a luminescent material which exhibits red emission by excitation with blue light (red emitting luminescent material) and a blue LED. In the green emitting luminescent material, a decrease in emission intensity is often caused by an increase in temperature of the blue LED. Since a decrease in emission intensity of the red emitting luminescent material is small, a balance between an emission by the blue LED and an emission by the luminescent material is easily lost.
A thermal quenching behavior of the green emitting luminescent material is different from that of the red emitting luminescent material and thus a balance of green and red is easily lost by an increase in temperature of the blue LED. Consequently, a balance between green light and red light from the luminescent materials and blue light from a light source is lost, which leads to a significant “color shift”. Therefore, there is a need for a green emitting luminescent material which exhibits a small decrease in emission intensity (thermal quenching) even if the temperature is increased.